custom namer support

naming.go

@@ -66,7 +66,7 @@ func ToColumnName(name string) string {
 	return TheNamingStrategy.ColumnName(name)
 }
 
-var smap = newSafeMap()
+var Smap = newSafeMap()
 
 func defaultNamer(name string) string {
 	const (
@@ -74,7 +74,7 @@ func defaultNamer(name string) string {
 		upper = true
 	)
 
-	if v := smap.Get(name); v != "" {
+	if v := Smap.Get(name); v != "" {
 		return v
 	}
 
@@ -119,6 +119,6 @@ func defaultNamer(name string) string {
 	buf.WriteByte(value[len(value)-1])
 
 	s := strings.ToLower(buf.String())
-	smap.Set(name, s)
+	Smap.Set(name, s)
 	return s
 }

naming_test.go

@@ -1,6 +1,7 @@
 package gorm_test
 
 import (
+	"bytes"
 	"testing"
 
 	"github.com/jinzhu/gorm"
@@ -29,6 +30,71 @@ func TestTheNamingStrategy(t *testing.T) {
 
 }
 
+func TestAddNamingStrategy(t *testing.T) {
+
+	// users can set their custom namer
+	custom := &gorm.NamingStrategy{
+		Column: CustomNamer,
+	}
+	gorm.AddNamingStrategy(custom)
+
+	// test
+	cases := []struct {
+		name     string
+		namer    gorm.Namer
+		expected string
+	}{
+		{name: "auth", expected: "auth", namer: gorm.TheNamingStrategy.DB},
+		{name: "userRestrictions", expected: "user_restrictions", namer: gorm.TheNamingStrategy.Table},
+
+		{name: "clientID", expected: "clientID", namer: gorm.TheNamingStrategy.Column},
+		{name: "Client0ID", expected: "client0ID", namer: gorm.TheNamingStrategy.Column},
+		{name: "_Client_ID_", expected: "_Client_ID_", namer: gorm.TheNamingStrategy.Column},
+	}
+
+	for _, c := range cases {
+		t.Run(c.name, func(t *testing.T) {
+			result := c.namer(c.name)
+			if result != c.expected {
+				t.Errorf("error in naming strategy. expected: %v got :%v\n", c.expected, result)
+			}
+		})
+	}
+
+}
+
+func CustomNamer(name string) string {
+	// set `smap` public access and users can use it to cache
+	if v := gorm.Smap.Get(name); v != "" {
+		return v
+	}
+
+	const (
+		lower = false
+		upper = true
+	)
+
+	var (
+		value    = name
+		buf      = bytes.NewBufferString("")
+		currCase bool
+	)
+
+	for i, v := range value {
+		currCase = bool(value[i] >= 'A' && value[i] <= 'Z')
+		if i == 0 && currCase == upper {
+			buf.WriteRune(v + 32)
+		} else {
+			buf.WriteRune(v)
+		}
+	}
+
+	s := buf.String()
+	gorm.Smap.Set(name, s)
+
+	return s
+}
+
 func TestNamingStrategy(t *testing.T) {
 
 	dbNameNS := func(name string) string {